[vtkusers] How to update the renderer when the data is modified?

[Glen Lehmann]

Hi Ali,

Yes, in 10 years VTK has done a great job of figuring this one out.
Do some browsing through the Wiki or grab one of the VTK books to
learn a bit more about the VTK pipeline.

In short, VTK is demand-driven.  You need to call Update() on your
vtkImageData after it is modified, this will update the pipeline.

HTH,

Glen

On 02/11/06, Ali - <saveez at hotmail.com> wrote:
> Hi,
>
> First of all, I think this should have been already implemented in VTK, the
> library is 10 years old! When some data is modified in the pipeline, the
> renderer does not get updated automatically.
>
> Trying the following ends up with the error: wglMakeCurrent failed in
> MakeCurrent(). What would the right way of implementing this? All I am doing
> is displaying an image with vtkImageViewer2, and all I want is the renderer
> to get updated automatically when the image data is modified.
>
> static void UpdateRenderer(vtkObject *vtkNotUsed( caller ),
>                            unsigned long vtkNotUsed(eventId),
>                            void *obj, void *)
> {
>   vtkImageViewer2* vw = reinterpret_cast<vtkImageViewer2*>(obj);
>   vw->Render();
> }
>
> main()
> {
>   vtkImageImport im = vtkImageImport::New();
>   // ...
>   vtkImageViewer2 *viewer = vtkImageViewer2::New();
>   // ...
>   vtkCallbackCommand *cbc = vtkCallbackCommand::New();
>   cbc->SetCallback(UpdateRenderer);
>   cbc->SetClientData((void *)viewer);
>   im->AddObserver(vtkCommand::RenderEvent, cbc);
>   cbc->Delete();
>   // ...
> }
>
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